Musical instrument



Dec. 15, 1942. J KQEHL MUSICAL INSTRUMENT 2 Sheets-Sheet 1 Filed Dec. 4,1941 11 HHHHHHHHHHHHill" WIHI'HMHI Dec. 15, 1942; I J. A. KOEHL2,305,575

MUS ICAL INSTRUMENT Filed Dec. 4, 1941 2 Sheets-Sheet 2 Patented Dec.15, 1942 MUSICAL INSTRUMENT James A. Koehl, Chicago, Ill., assignor toCentral Commercial Company, Chicago, 111., a corporation of IllinoisApplication December 4, 1941, Serial No. 421,605

(Cl. 84-l.01)

8 Claims.

This invention relates t musical instruments and has particularreference to the type of instrument disclosed in my prior Patent No.2,250,065, dated July 22, 1941, and has for its primary object theprovision of a new, novel and effective system of controls for thevarious electro-mechanical sound producing mechanisms herein employed.

An important object of the invention is to arrange the expression pedalsof a piano and the pedal clavier of my electric organ to enableinstantaneous shifting of the feet of the player from the pedal keys ofsaid pedal clavier to the expression pedals of the piano and vice versaaccording as changes in expression and musical effects are desired.

A still further object is to provide a piano with a pedal clavier whichis actuable substantially in the manner of the pedal clavier of any wellknown organ and whose relation to the keyboard of the piano is the sameas that of the pedal clavier to said organ, i. e. substantially mediallyof the compass of the notes of said keyboard.

While I preferably employ an expression pedal for controlling theamplitude of electrically produced sounds, in some instances, said pedalwill be omitted and some equivalent controlling means substitutedtherefor. This could be the case where my invention is sold as anattachment to a piano. With this in mind, it is a further object toprovide a pedal clavier which will readily accommodate the customaryexpression pedals of and without the necessity of structural alterationsto the piano.

The novel features of my invention are set forth with particularity inthe hereto appended claims. The invention itself, however, both as toits organization and its method of operation, together with additionalobjects and advantages thereof, will be morefully understood from thefollowing description of a preferred embodiment, when taken inconnection with the accompanying drawings, in which:

' Figure 1 is a view partly in end elevation and partly in section of myinvention;

Figure 2 is a view in front elevation thereof;

Figure 3 is a schematic illustration of one of the electrical circuitsemployed;

Figure 4 is a view in elevation of the hammer action;

Figure 5 is a detail view in elevation of a slightly modified form of myinvention, and

Figure 6 is a front elevation of the form shown at Figure 5.

r In carrying the invention into practice it will suffice to say thatthe electro-mechanical system herein employed may be the same as thesystem disclosed in my aforementioned prior patent.

In Figure 3, 5 represents an oscillator, the plate 6 of which isconnected by a circuit lead I with a contactor 8 of playing key 9 of thekeyboard Hl shown at Figure 2. The screen grid H of said oscillator maybe supplied with a controlling signal from any Well known frequencycontrolling source, not shown, such that the oscillator will deliver anoutput signal having the frequency of the musical note associated withsaid key 9. Circuit lead 1 has an electric switch [2 adapted when closecircuited to cause current flow to said key contactor 8. A contactor 13,together with contactor 8 completes an electric switch for said key,and, as shown, contactor l3 connects by a circuit lead M with a commonoutput conductor I5, the latter, in turn, connecting with an amplifyingand sound producing system l6. The system l6 comprises an amplifier l1,electrical sound producer I8 and a potentiometer 19. In this manner, andas is well known in the art, amplified alternating current from saidoscillator 5 will be converted into audible sound of any desiredamplitude and the sound sustained as long as desired. The potentiometerI9 is adapted to be actuated by an expression pedal which will be morefully referred to presently.

Connected in the circuit shown at Figure 3 is a pedal key 20, having anelectric switch consisting of contactors 2| and 22 which are opencircuited when the key is elevated. Contactor 22 connects by a circuitlead 23 with said common output conductor I5. Contactor 2| connects by acircuit lead 24 with the output lead I from oscillator 5, and, as shown,said lead 24 has an electric switch 25. When switch 25 is closecircuited and switch l2 in lead I is open circuited, output current fromsaid oscillator 5 is supplied contactor 2| of said pedal key 20. Upondepressing said pedal key the circuit thereby established causes currentto be conducted from said oscillator and impressed upon said outputconductor and translated into audible sound of any desired amplitude.With the circuit in the condition last stated, no current will beconducted to the contactor 8 of playing key 9 and the latter may be usedfor the playing of piano music. When switches l2 and 25 are both thereofclose circuited, current from oscillator 5 is fed to the electricswitches of keys 9 and 20 and impressed upon said output conductor l5upon depressing said keys.

If now, We assume that each individual playing key 9 will have anoscillator and an elec tric switch for controlling conduction of outputoscillations to the work circuit of my system, it follows that uponplaying said keys, sustained tones having the characteristics of organtones will be sounded and the tones sustained as long as desired.

At Figures 1 and 2 is shown a pedal clavier 2'! which is substantiallycoextensive with the case of the piano 28. Said clavier has a group ofkeys 29 situated at the left of the expression pedals 39-31 of the pianoand a similar group of keys 29 at the right of said expression pedals.These pedals are each thereof the same as pedal referred to in the abovedescription of the circuit shown at Figure 3 and each pedal will have aresilient switch actuator 32 adapted to enter a slot 33 in the case ofthe piano and lightly rest upon the contactor 21 of the electric switchwhich is individual to said key.

Said pedal clavier is detachable from the piano and by reason of themanner of grouping the pedal keys 29, the expression pedals 3i lie inthe plane of said clavier and are laterally spaced apart from adjacentkeys 29 as shown at Figure 2. In this manner, the feet of the player canbe shifted as desired from the keys of the clavier to the expressionpedals of the piano and vice versa and with required ease andconvenience during concurrent playing of piano and organ music. Wheneither type of music is played independently of the other, theexpression pedals 3i3-3l or the keys 29, as the case may be, can beoperated in the manner common to the organ and to the piano as will bereadily understood.

In order that the potentiometer can be conveniently controlled from thepedal section of my organization, I provide an expression pedal 32 whichis preferably set into the case of the piano where it occupies aposition above the expression pedals 38-4! and in back of the clavier.

This method of assembling the pedal keys 29 and expression pedals 3fl-3land 32, not only provides for compactness of the parts but enables anyof said parts to be controlled from customary positions and insuresinstantaneous actuation of said parts according as different musicalresults are desired.

Each pedal key 29 will have its circuit controlling electric switchesconnected with an oscillator whose output frequency corresponds to thevibration frequency of the musical note associated with said key.

In those instances Where the invention is employed as an attachment to apiano, the electric switches for the pedal clavier are preferablycontained in a housing organization disposed in front of the case of thepiano as shown at Figures 5 and 6. Said housing organization has asection 36 at the left of the expression pedals 303! and a similarsection 3'! at the right thereof. In this manner, the pedal clavier canbe readily associated with the piano without requiring any changes inthe construction of the case the instrument and the expression pedals39-39 w ll occupy their customary positions.

At Figure 4: is shown a conventional piano a tion as. A single playingkey 9 is illustrated. The hammer for said key has its shank restingagainst a manually shiftable stop 40. When. the stop is advanced againstthe shank, the hammer will bear against the string 42 where it Will benon-responsive to motion of the key 9, thereby enabling electricallyproduced music to be rendered independently. As this feature has beenfully described in my aforementioned prior patent, no furtherdescription is deemed necessary.

To the best of my knowledge no one has ever before combined a pedalclavier with the keyboard of a piano, and I therefore reserve the rightto employ said clavier in association with any well known system havingfor its purpose the electrical production of organ tones. In someinstances, said pedal clavier can comprise the Whole of the inventionherein disclosed and may be attached to a piano for coaction therewithto produce chorus, solo and many novel musical effects. While I haveshown a pedal clavier having but twenty-five pedal keys, the number ofkeys can of course be either increased or decreased Without departingfrom the spirit of my invention.

What I claim as my invention is:

1. In an electro-mechanical musical instrument employing a keyboard,tuned strings, an action operated from said keyboard for vibrating saidstrings. a system of generators of tone signal currents includingelectro-acoustic means for translating said signal currents into audiblesounds, means actuable by the playing keys of said keyboard forrendering selected tone signal currents effective upon said translatingand expression pedals for controlling the volume of sound produced bysaid strings; a pedal board, the pedal keys of Which and said expressionpedals occupy substantially the same horizontal plane, means actuable bysaid pedal keys for rendering tone signal currents effective upon saidtranslating means from selected generators of said system of generators,an expression pedal disposed above the aforementioned expression pedalsand in back of said pedal keys, and means actuable by the last namedxpression pedal for controlling the amplitude of sound produced by saidtranslating means.

2. In an electro-mechanical musical instrument employing a case having akeyboard, tuned strings, an action operated from said keyboard forvibrating said strings, a system of generators of tone signal currentsincluding electroacoustic means for translating said signal currentsinto audible sounds and means actuable from said keyboard for renderingtone signal currents effective upon said translating means, andexpression pedals for controlling the volume of sound produced by saidstrings; a pedal board, the pedal keys of which and said expressionpedals occupy substantially the same horizontal plane, means actuable bysaid pedal keys for rendering tone signal currents effective upon saidtranslating means from selected generators of said system of generators,an expression pedal set into the case above the plane of theaforementioned expression pedals and in back of said pedal keys, andmeans actuable by the last named expression pedal for controlling theamplitude of sound produced by said translating means.

3. The combination with a piano including its case, expression pedalsand a keyboard, of a pedal keyboard extending substantially from one endof the case to the other end thereof and provided with a group of pedalkeys disposed at the left of said expression pedals and a group of pedalkeys disposed at the right thereof, an electrical tone signal generatingsystem, and means actuable by said pedal keys for rendering effectiveupon an electroacoustic translating means selected electricallygenerated tone signals from said signal generating system.

4. The combination with a piano including its case, expression pedalsand a keyboard, of a pedal keyboard extending substantially from one endof the case to the other end thereof and provided with a group of pedalkeys disposed at the left of said expression pedals and a group of pedalkeys disposed at the right thereof, an electrical tone signal generatingsystem, an electroacoustic translating device for conversion of tonesignal current generated by said system into audible sound, meansactuable by said pedal keys for rendering signal current effective uponsaid translating device upon depression of any selected pedal key, andan expression pedal set into said case above said expression pedals andin back of said pedal keys.

5. The combination with an electrical system for the selectivecontinuous generation of currents of audible frequency and a piano, theplaying keys of the keyboard of which are in electrical coaction withsaid system to enable selective conduction of signal current to a workcircuit; of a pedal keyboard, the keys of which are also in electricalcoaction with the aforementioned electrical system to enable selectiveconduction of signal currents to said work circuit, the expressionpedals of said piano extending into the plane of said pedal keyboard andspaced apart laterally from adjacent keys thereof.

6. The combination with an electrical system for the selectivecontinuous generation of currents of audible frequency and a piano, theplaying keys of the keyboard of which are in electrical coaction withsaid system to enable selective conduction of signal current to a workcircuit; of a pedal keyboard extending approximately the full length ofthe case of said piano, the keys of said pedal keyboard also havingelectrical coaction with the aforementioned electrical system to enableselective conduction of signal current to said work circuit, theexpression pedal of said piano extending into the plane of said pedalkeyboard and spaced apart laterally from adjacent keys thereof.

7. The combination with an electrical system for the selectivecontinuous generation of currents of audible frequency and a piano, theplaying keys of the keyboard of which are in electrical coaction withsaid electrical system to enable selective conduction of signal currentto a Work circuit; of a pedal keyboard, the keys of which are also inelectrical coaction With the aforementioned electrical system to enableselective conduction of signal current to said work circuit, theexpression pedals of said piano extending into the plane of said pedalkeyboard and spaced apart laterally from adjacent keys thereof, and anexpression pedal set into the case and above the plane of saidexpression pedals of the piano and in back of said pedal keyboard.

8. The combination with an electrical system for the selectivecontinuous generation of currents of audible frequency and a piano, theplaying keys of the keyboard of which are in electrical coaction withsaid system to enable selective conduction of signal current to a workcircuit; a pedal keyboard detachably affixed to the case of said piano,the keys of said pedal keyboard also having electrical coaction withsaid electrical system to enable selective conduction of signal currentto said work circuit, the expression pedals of said piano extending intothe plane of said pedal keyboard and spaced apart laterally fromadjacent keys thereof.

' JAMES A. KOEHL,

